Introduction

This project will provide shipyards with current exposure levels associated with select welding processes and also techno-economic alternatives for meeting the new anticipated standards for Cr(VI) for welding operations carried out in shipyards.  This research was prompted by the Occupational Safety and Health Administration's (OSHA's) anticipated rulemaking to reduce welder exposure to Cr(VI) from 100 to between 0.5 and 5 g/m³.

Background

Welding is one of the important metal processing operations in shipyards. Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Gas Tungsten Arc Welding (GTAW), and Flux-Cored Arc Welding (FCAW) are commonly performed. The Oil, Chemical, and Atomic Workers (OCAW) Union drew the attention of OSHA with regard to the carcinogenic effect of Cr(VI) in welding fumes. OSHA responded by proposing to bring down the permissible exposure level (PEL) of Cr(VI) from 100 g/m³ to a value between 0.5 to 5 g/m³.

Shipyards believed that the proposed rulemaking would have serious economic and technical impact.  The necessity to assess this dramatic techno-economic impact was felt among the various commercial and naval shipyards.  The University of New Orleans (UNO) joined the bevy of researchers to address the problem.  The project plans to study various welding processes, both with, and without, engineering controls.  For each of the processes studied the project hopes to evaluate its relative technical and economic merits. Avondale shipyards and Newport News are the industry collaborators for UNO.

Objectives

The main objective of the UNO study is to evaluate Cr(VI) exposures to specific welding processes (GMAW & FCAW) on specific materials (HY-100 and DH-36) and to evaluate techno-economic compliance procedures for selected alternatives to meet the anticipated new standards of OSHA.

Applications

Naval shipyards

Commercial shipyards and boat yards

Other industries using the same welding methods

Development Partners

Newport News Shipyard

Avondale Shipyards

Naval Surface Warfare Center-Carderock Division (NSWCCD)

Naval Facilities Engineering Services Center, NAVOSH Air Branch

Modules

The flowchart below lists the important modules involved in this project.  The modules listed in the flowchart are discussed in detail below.

Tech. Alternatives ---> Experimental Design ---> Procurement of Equipment ---> Sampling ---> Analysis ---> Feasibility Analysis ---> Prioritization of Tech. Alternatives

1) Review of Applicable Technical Alternatives
The selection of technical alternatives such as the welding guns with vacuum heads, stationary and portable fume extraction systems applicable to shipyards welding will be considered in this module.  Discussions to identify specific welding processes for study are also a part of this module.

2) Experimental Design
Under this module, the welding parameters such as the arc time, type of area setting, ventilation type (area, local, and positioned) and fume extraction systems will be decided.

3) Sampling of Airborne Fumes
The task includes sampling of airborne fumes using personal air pumps recommended for Cr(VI) evaluation. The recommended sampling rate is 110 in³/min (2 litres per minute). The Cr(VI) fumes are collected in a Poly Vinyl Chloride filters embedded in a polystyrene cassette. The Cr(VI) is then extracted from the filter using an aqueous solution of 10% sodium carbonate and 2% sodium bicarbonate. Area samples will also be collected to assess worker exposure to Cr(VI).

4) Analysis of Airborne Fumes
This task includes the analysis of airborne fumes for Cr(VI) using the OSHA recommended method. The analysis method employs Ion Chromatograph (IC).
 
5) Exposure Data Analysis
Laboratory results will be analyzed to calculate the eight-hour time weighted averages (8-hr.-TWA) of Cr(VI) exposure. For comparative purposes, a single arc time will be used. Results will be compared with the anticipated PELs of Cr(VI)  to check for compliance.

6) Cost Data Analysis
For the alternatives studied under this project, the cost information will be gathered and analyzed.

7) Prioritization of Techno-Economic Alternatives for Compliance
The various technical alternatives will be rated on the basis of their of technical merit and costs. The best alternatives for compliance will be recommended.

For more information contact:

Bhaskar Kura, Ph.D.
Telephone: 504-280-6572
Fax: 504-280-5586
E-Mail: bxkce@uno.edu

The contents of this publication reflect the views of the MERIC staff and are based on information obtained from the literature.  The contents do not necessarily reflect the official views or the policies of MERIC or the Gulf Coast Maritime Technology Center.  This publication does not constitute a standard, specification, or regulation.  MERIC does not endorse products, equipment or manufacturers.  Trademarks or manufacturer's names appear herein only because they are considered essential to the object of this publication.